An extremely stretched out vaginal hole. This is due to frequent sex with many partners. Aside from being extremely large and therefore being unable to satisfy men the S. Barr often smells. Think St. Paul Pork Products.

"Damn girl you have a S. Barr! I can't do it wid you no moe."
"What?"
"A Sara Bartlett, and it fuckin smells you might wanna clean that shit."